Man-pack antenna



Nov.

27, 1951- LENSE 2,576,128

MAN-PACK ANTENNA Filed April 5, 1948 FIG. I

INVENTOR. Ralph J. Lense Patented Nov. 27, 1951 2,576,128 MAN-PACKANTENNA Ralph J. Lense, Deerfield, IlL, assignor to Motorola, Inc.,Chicago, 111., a corporation of Illinois ppli a i Ap l 1948,. rial N9-18589 6 Claims.

This invention relates to antennas for portable radio equipment and thelike, and it has particular reference to an antenna adapted to be wornwith or concealed under the clothing of the user.

There are some situations in which wearable antenna are very desirable.In military usage. for example, a concealed antenna is highlyadvantageous because it gives no indication to the enemy that acommunication set is being carried on the person. Such an antenna alsohas the advantage that there are no projecting parts which are likely tobecome caught on obstructions or which are exposed to rain, mud or thelike. However, there has been a serious problem of keeping thecapacitybetween the antenna and the body of the wearer sufliciently low so thatthe antenna will not be critical in its operation. Prior antennas wereaffected by movements of the-wearer and were sensitive to the varyingbody capacities of different individuals.

An object of the present invention is to provide an improved wearableantenna constructed so that a very low capacity exists between theantenna conductor and the body of the wearer whereby the tuning of theantenna is quite broad.

Another object is to provide a novel man-pack antenna which is extremelyflexible so as not to hamper the movements of the wearer.

A still further object is to provide an improved wearable antenna ofsimple and economical construction in which the antenna capacity has alow, substantially constant value unaffected by difierent bodycapacities and positions of use.

7 A primary feature of the invention is the formation of sufiicient aircells or spaces in the antenna insulation so that the dielectric betweenthe antenna conductor and the wearers body is mostly air.

Another feature of the invention consists in providing two layers ofdielectric tubing (spaghetti insulation) which are spirally wound inopposite directions around the antenna conductor.

Still another feature is the provision of an outer serving which has anextended end or pigtail that can be fastened about a part of thewearer's body.

The foregoing and other objects, features and advantages of" theinvention will be apparent from a study of the following descriptiontaken in connection with th accompanying drawing, wherein:

Fig. 1 is a partially schematic elevational view Fig. 2 is a schematicillustration of a portable radio system utilizing such an antenna;

Fig. 3 is a cut-away view of the antenna structure; and

Fig. 4 is a detail view of the extended end or pigtail of the antenna.

In practicing the invention, an insulated antenna conductor is coveredby two layers of spa hetti insulation which are spirally wound inopposite directions, and an outer serving of fab ric, rubber or other,suitable material, is placed over the spirally wound layers. Thecapacity of the antenna is low since the dielectric is mostly air. Twosimilar antenna sections are employed, one being adapted to extend alongthe upper" portion of the wearers body, while the other depends from thewearerswaist adjacent one of his legs, thereby affording a dipole. Bymeans of the pigtail at the upper end of the antenna the upper section ifastened to the wearers shoulder, and the lower section is similarlyfastened to the wearers leg. The upper and lower antenna sections areconnected together by a variable inductor which constitutes the primaryof an input transformer for a receiver or other piece of radio equipmentcarried by the wearer. The antenna has very broad tuning so that it isnot sensitive to changes of body capacity or movement of the wearer.

Referring now to the drawing, the antenna there shown is of the dipoletype which comprises an upper section [0- and a lower section I 2. Theupper section II! extends from the waist of the wearersbody M to a pointadjacent to the wearers shoulder, while the lower section I2 dependsfrom the wearers waist-adjacent a leg and may terminate near the knee.Each section It or l2 has an outer serving 16 which is extended past theantenna proper at one end thereof to afforda pigtail I8. The pigtails l8serve to fasten the antenna sections tothe shoulder and leg,respectively; of the wearer.

Each antennasection has at its core an antenna conductor 20 which may beinsulated by solidmaterial as indicated at- 22. Surrounding this core isa layer of dielectric tubing or. Spa.

may be advisable also to seal the ends of the;

spaghetti insulation to prevent water from being drawn therein bycapillary action. However, the insulating tubes should not be gluedtogether, as this would form a rigid cylinder and destroy theflexibility of the antenna.

The radio equipment such as the receiver 30 carried by the wearer iscoupled in any suitable manner to the secondary =32 of an antenna inputtransformer 34 carried at the waist. The primary 36 of the transformer34 is connected at its ends respectively to the conductors 20 in the twosections and I2 of the antenna; The transformer 34 is provided with amovable core 38 for inductance tuning of the antenna system. It will beapparent from the foregoing description that I have provided an antennastructure which is not critical and in which the tuning of the antennais very broad, due to the low capacity between the antenna conductorsand the body of the wearer. The porous or cellular contruction of theinsulation gives an effective dielectric constant not substantiallygreater than unity. The layers of plastic tubing 24 and 26 minimizerelative movement between the antenna conductors 2B and the wearersbody. The movements of the wearer are not hampered by this arrangement,and the structure is very inconspicuous when worn.

While a preferred embodiment of the invention has been disclosed herein,this obviously is capable of modification, and it is intended that theappended claims cover all modifications coming within the abovedescribed principles.

I claim:

1. A man-pack antenna of the dipole type comprising a first conductoradapted to extend ductors, a plurality of layers of flexible dielec-.

tric tubing spirally wound indifferent directions about each of saidconductors, and an outer serving for each portion of the antenna.

2. An antenna structure as set forth in claim 1, wherein the upper endof said serving is extended for fastening to the shoulder of the wearer,and the lower end of saidserving extended for fastening to the leg ofthe wearer.

3. An antenna adapted to be worn on a human body including incombination, flexible antenna conductor means, and insulating means forsaid conductor means including two layers of flexible dielectric tubingspirally. wound one on top of the other in opposite directions aroundsaid conductor means and an outer serving enclosing said layers oftubing, said serving extending be-,

yond the ends of said conductor means for securing said antenna at theopposite ends thereof to the body of the wearer, said conductor means.

extending over a substantial portion .of the height of the user, saidinsulating 'means beingso constructed that said antenna yields to bodilymovements of the user and that the capacity be- 4 tween said conductormeans and said human body is low.

4. An antenna of the dipole type adapted to be worn on the human bodyand to have low capacity with respect to the human body including incombination, a pair of antenna conductor means extending substantiallyin a line, coupling means for connecting said conductor means to anelectronic device, flexible insulatin means about said conductor meanshaving a dielectric constant not substantially greater than unity, andmeans for supporting said antenna and securing the same to the body ofthe wearer,

said conductor means and said insulating means being so constructed thatsaid antenna yields to bodily movements and the capacity between saidconductor means and the body is not changed substantially by said bodilymovements.

5. An antenna of thesdipole type adapted to be worn on the human bodyand to have low capacity with respect to the human body comprising, apair of elongated conductors, coupling means connected to one end ofeach of said c0n'-- ductors, flexible insulating means about saidconductor means having a dielectric constant not'substantially greaterthan unity, and means for supporting said antenna onthe body of thewearer including means for supporting said coupling means at the waistandfor supporting the ends of said conductors not connected to saidcoupling means, one at the shoulder of the wear er and the other at theleg of thewearer, said conductor means and said insulating means beingso constructed that said antenna yields to bodily movements and thecapacity between said conductor means and the body is not changedsubstantially by bodily movements.

6. An antenna adapted to be worn on a human body, including incombination, flexible antenna conductor means, insulating means for saidcon-' ductor means including afirst layer of flexible dielectric tubingspirally wound about said conductor means and a second layer of flexibledielectric tubing spirally wound about said first layer in a directionopposite to the direction of said first layer, and supporting --meansfor said antenna including a portion surrounding said layers of tubingand a portion for securing said antenna to the body of the wearer,saidconducting means extending over a substantial portion of the height ofthe wearer, said insulatingmeans being so constructed to provide a lowcapacity between said conductor means and said human body and to yieldreadily tomo'vements of said human body.

REFERENCES CITED The following references are of record in the file ofthis patent: V

UNITED STATES PATENTS RALPHJ. LENSE. f'

